The present invention pertains to the field of portable or battery-operated lighting products. More particularly, this invention relates to hand-held, battery-operated flashlights.
Flashlights are used to cover a variety of household, workplace and recreational needs. Common flashlights often include a head that contains a relatively fragile incandescent bulb, and a cylindrical body configured to hold batteries. A switch, commonly mounted in the body, completes a circuit between the batteries and the bulb. A parabolic mirror or reflector is located within the head, with the filament(s) of the bulb positioned at the focal point of the mirror. The mirror directs rays of light from the filament forward in a parallel direction, creating a useful beam, as depicted in FIG. 1A. In some cases, such flashlights are provided with rubber o-rings to form a water-tight seal on the flashlight.
Many flashlights are stored without usage for great periods of time, and can be then called upon to provide light for long periods with little notice. Other flashlights are used frequently, and can be subject to significant environmental extremes such as shock and temperature. In either case, failure of the flashlight's fragile bulb is an all-to-frequent occurrence, leaving a user without a useful light source. Time efficiency often dictates that the entire flashlight, rather than just the bulb, be replaced, making the loss of a bulb relatively expensive.
As much as 50% of the light produced by the filament will miss the parabolic mirror (in either a forward or rearward direction), causing a large portion of the light to be widely radiated out in many directions, as depicted in FIG. 1B. While this peripheral light is sometimes useful, it is nothing but wasted glare in many situations. Other common problems experienced by such flashlights include batteries that do not provide light for an adequately extended period, particularly after the flashlight has been in use or in storage. A further problem is that if the bulb filaments are not precisely positioned at the focal point of the parabolic mirror, the light striking the mirror will not be directed in a parallel beam, further reducing the effectiveness and efficiency of the flashlight.
Accordingly, there has existed a definite need for a durable flashlight configured to provide an effective useful beam for an extended period, particularly after extended storage. The present invention satisfies these and other needs, and provides further related advantages.